Parents of teenage boys often believe they are being eaten out of house and home. A new study suggests they're right.
In a lunch-buffet experiment involving 200 kids ages 8 to 17, researchers found that boys routinely ate more compared with girls their own age. But boys in their mid-teens were the most ravenous of all - downing an average of nearly 8,400 lunchtime kilojoules.
The pattern makes sense, given that boys usually hit their growth spurt - putting on height and muscle mass - in late puberty, according to senior researcher Dr Jack A. Yanovski, of the US National Institute of Child Health and Human Development.
Yet, while teenage boys have a storied reputation for packing it away, there had actually been little objective evidence that this is the norm.
"There's a lot of folk wisdom that says boys can eat prodigious amounts, but we haven't had much data," Yanovski told Reuters Health.
To fill the gap, he and his colleagues had 204 8- to 17-year-old boys and girls come to a lunch buffet on two separate days. On one day, the kids were instructed to eat as much as they normally would during lunch; on the other day, they were told to eat as much as they wanted.
Overall, the researchers found, boys ate more than girls did at each stage of puberty. Prepubescent boys - generally between the ages of 8 and 10 - averaged nearly 5,460 lunchtime kilojoules, versus 3,780 among prepubescent girls.
Girls showed the biggest increase in appetite during early- to mid-puberty, roughly between the ages of 10 and 13. Girls that age averaged almost 5,460 lunchtime kilojoules, and that figure was only slightly higher among girls who were in late puberty.
That pattern is in line with girls' development, Yanovski said, as they tend to have their most significant growth spurts in early- to mid-puberty.
Boys develop later
Boys, on the other hand, tend to develop later. And their kilojoule needs appear to shoot up significantly in late puberty, or between the ages of 14 and 17.
While boys in this study showed little change in kilojoule intake between pre- and mid-puberty, their average lunchtime kilojoule intake reached nearly 8,400 kilojoules in late puberty. Even for active children, those 8,400 kilojoules would be most of their daily energy needs.
"They really can eat," Yanovski noted.
For parents, he said, the findings offer an idea of what they can reasonably expect as far as their children's kilojoule needs, and the family grocery bills, as kids get older.
And as long as their teenage sons are healthy and normal-weight, a sudden surge in eating should not be alarming, according to the researcher.
On the other hand, Yanovski added, boys who are overweight should have more limits on how many kilojoules they down. Studies suggest that a majority of overweight kids become overweight adults. - (Amy Norton/Reuters Health, June 2010)
SOURCE: http://www.ajcn.org/cgi/content/abstract/ajcn.2010.29383v1 American Journal of Clinical Nutrition, online May 26, 2010.